DTC Advanced Diagnostics: P2648, P2649
DTC P2648:Rocker Arm Oil Control Solenoid Circuit Low Voltage
DTC P2649:Rocker Arm Oil Control Solenoid Circuit High Voltage

General Description

The VTEC system activates the rocker arm oil control solenoid by a command from the powertrain control module (PCM), and it charges/discharges the hydraulic circuit of the VTEC mechanism that switches valve timing between low and high. If the return signal is OFF (low) when the PCM outputs the ON (high) signal to the rocker arm oil control solenoid or the return signal is ON (high) when the PCM outputs the OFF (low) signal to the rocker arm oil control solenoid, the PCM detects a malfunction and stores a DTC.

Monitor Execution, Sequence, Duration, DTC Type
Execution
Continuous
Sequence
None
Duration
2.0 seconds or more
DTC Type
One drive cycle, MIL on

Enable Conditions
Condition
Minimum
Maximum
12 volt battery voltage [BATTERY]
10.0 V
–
[ ]: HDS Parameter

Malfunction Threshold
DTC: P2648

The return signal is OFF (low) for at least 2.0 seconds when the PCM outputs the ON (high) signal to the rocker arm oil control solenoid.

DTC: P2649

The return signal is ON (high) for at least 2.0 seconds when the PCM outputs the OFF (low) signal to the rocker arm oil control solenoid.

Possible Cause
NOTE: The causes shown may not be a complete list of all potential problems, and it is possible that there may be other causes.
DTC: P2648
Rocker arm oil control solenoid VTS line short to ground

DTC: P2649
Rocker arm oil control solenoid VTS line open
Rocker arm oil control solenoid ground line open

Common
Rocker arm oil control solenoid failure
PCM internal circuit failure

Confirmation Procedure
DTC: P2648

Operating Condition
1.
Start the engine. Hold the engine speed [ENGINE SPEED] at 3,000 rpm without load (CVT in P or N, M/T in neutral) until the radiator fan comes on.
2.
Drive the vehicle at a steady engine speed [ENGINE SPEED] at 1,400 rpm or morewith a vehicle speed [VEHICLE SPEED] at 10 mph (15 km/h) or more for at least 16 seconds.
Drive the vehicle in this manner only if the traffic regulations and ambient conditions allow.
With the HDS
Do the VTEC TEST in the INSPECTION MENU with the HDS.

DTC: P2649

Operating Condition
Start the engine, and let it idle for at least 3 seconds.

With the HDS
None.

Diagnosis Details
Conditions for setting the DTC
When a malfunction is detected, the MIL comes on and a Pending DTC, a Confirmed DTC, and the freeze data are stored in the PCM memory.

Conditions for clearing the DTC
The MIL is cleared if the malfunction does not return in three consecutive trips in which the diagnostic runs. The MIL, the Pending DTC, the Confirmed DTC, and the freeze data can be cleared with the scan tool Clear command or by disconnecting the 12 volt battery.